Studies of histone interactions in solution will give information on the possible roles of histone interactions in the packaging of DNA and the mediation of gene activity. These studies are being conducted by sedimentation-equilibrium techniques. These experiments are unusual in that competing interactions are present, and the concentrations of a number of species must be determined. New sedimentation-equilibrium techniques, combining data from many experiments in a single analysis, are being developed to achieve these analytical goals. BIBLIOGRAPHIC REFERENCES: Carlisle, N. M., J. I. H. Patterson, and D. E. Roark. "An Automated Microcomparator for Ultracentrifuge Interference Fringe Measurements". Analyt. Biochem. 61, 248-263 (1974). Geoghegan, T. E., G. H. Keller, and D. E. Roark. "Properties of Calf-Thymus Histones Isolated by Non-denaturing Methods". Fed. Proc. 33, 1598 (1974).